Where does the phrase “blowing one’s top” come from and What does it mean?

December 15, 2019 by Karen Hill

Possibly the “top” in the expression “blowing one’s top” alluded originally to the top of a volcano, which would be shot into a thousand pieces with a tremendous noise during a violent explosion and scattered over the neighborhood with a devastating effect.

“Blow,” at least, has been used in the sense of “to erupt; to go to pieces by explosion” for several centuries.

Much the same effect occurs when, in modern slang, a person “blows his top.” He lets off steam in a violent explosion of temper; he shouts; he cares not a whit where or upon whom the pieces may fall.

In short, he gets furious with rage.

The expression is also used in a far milder sense: a crazy person, that is, or a person who is befuddled by drink and acts brainless is now sometimes said to have blown his top.